Running Hot
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Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 18 July 2011 - 12:27 PM

I have a '68 Firebird convertible I have owned since 2002. It is a 350, 4 barrel car pretty much in factory set up. I know it is VERY hot this summer, but my car seems to running really hot on city streets, stoplight to stoplight. Would an electric fan solve this problem? I want to keep my stock fan in place. I have the A/C panels from a 400 car in place so the additon of an electric fan wouldnt even be seen. When I bought my car, the previous owner had intalled a new radiator with an overflow tank. I relocated the overflow tank in front of the radiator support, about 3 inches lower than the top of the radiator support. Any suggestions? Thanks in advance for any help, Lee

Lee...does it have a fan shroud? Might be a funny question..my 69 Firebird didn't have one and when I installed my electric fan I didn't think I needed one...still overheated sitting in idle...made a custom fan shroud and now it runs at 195-200 degrees on 105 degree Oklahoma days.

Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 22 July 2011 - 01:57 PM

I do have a reproduction fan shroud on it. I replaced te thermostat with a Delco 195 degree unit. Still no change. Its running about 210 on the highway and about 230-235 on asphalt streets. Is an electric fan my next step? The guy I bought my car from destroyed the original fan and replaced it with what appears to be a flex style fan. When I rev it up, the blades eem to change pitch.

Your fan clutch maybe going bad. If this is the case your fan isn't spinning fast enough to keep the proper flow of air through your radiator causing the car to run hot. If the flex fan is changing pitch this may also be causing your problem. I would try to find a stock fan and replace the clutch along with a radiator flush. :crossfingers22:

I do have a reproduction fan shroud on it. I replaced te thermostat with a Delco 195 degree unit. Still no change. Its running about 210 on the highway and about 230-235 on asphalt streets. Is an electric fan my next step? The guy I bought my car from destroyed the original fan and replaced it with what appears to be a flex style fan. When I rev it up, the blades eem to change pitch.

If it runs 210 on the highway, I don't think it has anything to do with the fan, which probably wouldn't even run in that case. Look for coolant restrictions, like a plugged radiator, collapsed hoses, bubbles in the coolant (bad news), I assume the water pump's turning ok. Does the cooling system hold pressure? Are you loosing any coolant when this happens?

1998 Trans Am - LS1/A4 - all stock and almost all original - one owner - driven daily

Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 23 July 2011 - 07:41 AM

When my car is hot and I shut it off, my hoses are tight so I am assuming my water pump is working. Is there an easy way to test the pump? I have never seen any bubbles in the radiator. I'm going to try to flush it and see where that goes. Thanks again for all of your help and suggestions!!

When my car is hot and I shut it off, my hoses are tight so I am assuming my water pump is working. Is there an easy way to test the pump? I have never seen any bubbles in the radiator. I'm going to try to flush it and see where that goes. Thanks again for all of your help and suggestions!!

Your hoses are tight because there is pressure built up from the heat, which wants to turn into steam....just like an old fashioned pressure cooker. They would get tight even if your pump did not work.

As for testing the pump...not really any way to check it apart from taking it out. You might have damaged/failed impellers, which would slow down the speed of water circulation, hence leading to running hot.

Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 25 July 2011 - 05:23 PM

I tried a new (195 degree) thermostat--no change. I put a 160 degree in--it stayed cooler for a while then hgit 235 again. I leave the car at my dads--so I cant flush it myself. So, I'm gonna take it in to have it flushed. Dad is afraid of getting antifreeze on the ground--they are on well water.

Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 26 July 2011 - 11:56 AM

I stopped at a radiator shop today--I'm going to take the radiator to them to have it looked at. They think it needs to be cut apart and rodded out. I've driven it about 24,000 miles in the last nine years, maybe its plugged up. I know the radiator is about ten years old, maybe its time. Will post again with the results. Thanks to everyone for your help.

Interests:i enjoy drivin my bird on a nice day on a two lane black top in the middle of the desert with me and the ride and wind lol/ and cars and women for sure

Year: 1979

Make: Pontiac

Model: Firebird Espirit

Engine: 1968 Pontiac 400

Transmission: Turbo 350

Posted 30 August 2011 - 06:42 PM

hey guys saw this post and had to get on it i am expiriencing this same exact problem i have a 69 400 in a 79 bird. most the time it runs around 190 to 210 but sometimes in traffic in phx it jumps up to 230 and it worries me i dont wanna mess anything up i changed my thermostat to a 195 its still doing the same thing. i notice as well the radiatior fluid is kinda green but it has a rust color to it the motor was rebuilt 6,000 miles ago im assuming someone may have flushed it before the rebuild but im not sure is this rust color a symptom of a filthy radiator if so i need an answser cuz ill clean it asap. this could be my problem i just need a little info thanks guys!!

Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 31 August 2011 - 11:10 AM

**UPDATE** I have an appointment on Friday to have my Firebirds radiator flushed forwards and backwards, the guy I talked too seemed to know what he is doing. Once again, thanks to EVERYONE for your helpful suggestions! This site is AWESOME! I will post the results of the "flush" soon.

Interests:Restoring my car. Driving it with the top down on a hot day with classic music from the 70's playing is about the best time in the world!

Year: 1968

Make: Pontiac

Model: Firebird

Engine: 350 Pontiac

Transmission: Auto-2 Speed

Posted 31 August 2011 - 11:17 AM

Hi Jimmy! I'm certainly no mechanic but I can share with you what i have learned by interviewing every radiator shop in town. I have been told a complete flush of the entire cooling system is the best place to start. Here in wichita, Kansas its going to be about $100. To me, its well worth the money because we both know what an engine costs. Good luck, friend. Let me know how it turns out. Lee

jimmyjam9193, on 30 August 2011 - 06:42 PM, said:

hey guys saw this post and had to get on it i am expiriencing this same exact problem i have a 69 400 in a 79 bird. most the time it runs around 190 to 210 but sometimes in traffic in phx it jumps up to 230 and it worries me i dont wanna mess anything up i changed my thermostat to a 195 its still doing the same thing. i notice as well the radiatior fluid is kinda green but it has a rust color to it the motor was rebuilt 6,000 miles ago im assuming someone may have flushed it before the rebuild but im not sure is this rust color a symptom of a filthy radiator if so i need an answser cuz ill clean it asap. this could be my problem i just need a little info thanks guys!!

Hi Jimmy! I'm certainly no mechanic but I can share with you what i have learned by interviewing every radiator shop in town. I have been told a complete flush of the entire cooling system is the best place to start. Here in wichita, Kansas its going to be about $100. To me, its well worth the money because we both know what an engine costs. Good luck, friend. Let me know how it turns out. Lee

210 is about what the engine should run at. If it is running at that while at highway speeds, then your water pump and radiator are probably fine. The issue would be fan related. While at highway speeds, the fan has no effect on the cooling system since the speed of the air on the car doing 65ish is faster than what the fan would blow anyway. If you are getting hot while in stop and go situations on normal city streets, then your fan is not moving air fast enough through the radiator. I think someone else may have mentioned it, but the fan clutch may be bad and therefore not turning the fan at the right speed. I'd probably look at either replacing the fan or switching to electric fans.

GaryDoug, on 22 July 2011 - 07:03 PM, said:

If it runs 210 on the highway, I don't think it has anything to do with the fan, which probably wouldn't even run in that case. Look for coolant restrictions, like a plugged radiator, collapsed hoses, bubbles in the coolant (bad news), I assume the water pump's turning ok. Does the cooling system hold pressure? Are you loosing any coolant when this happens?

210 on the highway is about what it should be running at. (meaning the cooling system is running fine)

His issue with running hot is when he is not driving on the highway. This would indicate it IS an issue with the fan.